hello, i am new to the site and am in need of some guidance on troubleshooting my car's problem. i have a 1992 bmw 318i (e30, 152,000 miles). lately i have had some issues starting the car, CEL comes and the fault is 1215 for air mass sensor. i have virtually all new hoses, air boot, and idle control valve less than 15,000 miles old. i check for possible leaks in any of the hoses around air mass, throttle body and fuel filter but dont find anything catastrophic, being that they are relatively new. next, i purchase a used air mass sensor, replace it, unplug battery to reset fault codes, and same problem exits, but now no fault code appears, just still having problems starting. it doesnt happen all the time though, if i let the car sit over night it seems to start fine in the morning, but after running the car for say 30 mins (no issues while car runs) and then kill the engine to test start, the car just doesnt want to start.

sorry for the brief novel above but i figured i would preface the situation. any help would be much appreciated.

this morning the car cold starts fine...after parking at work turn off engine, and try to start the car and no luck, try like 5 times. first try it starts and runs for a second, then dies. next couple of tries everything turns over and hear the engine start erratically while the MPG gage is fluttering back and forth and just dies. last try all you hear is the sputtering and but no engine catching. its got a lot of relatively parts including hoses, air boot, idle control valve, spark plugs, thermostat, water pump, fuel filter. i know the problem could be a number of things i just need to know where to start ruling things out since i have replaced the air mass meter.